Pulse interval divider



Filed July 5, 1956 R. L. HRONEK ET AL PULSE INTERVAL DIVIDER n.. Khun a NW1 mv\\\\\woo\ ob..

June 25, 1957 w om VIK@ l J Unite States PULSE INTERVAL DVIDER Robert L. Hronek, Mineola, N. Y., and Harry Cook, North Plainfield, N. J., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Application lilly 5, 1956, Serial No. 596,119

8 Claims. (Cl. Z50-27) The present invention relates to novel and improved electrical pulsing apparatus and more particularly to a novel and improved electronic circuit which is capable of receiving periodic electrical signals of a pulse train and dividing the periods between successive signals thereof into a predetermined number of equal subperiods.

It is a principal object of the present invention to provide a novel and improved pulse interval dividing circuit which is reliable in operation and yet relatively simple in construction.

It is a further object of the present invention to provide a novel and improved pulse divider circuit which can handle a wide range of repetition periods and which is free from spurious outputs.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

Figure l is a diagrammatic View of a preferred embodiment of the present invention.

In general the improved pulse dividing circuit of the present invention includes a free-running multivibrator circuit which controls the step-by-step energization of a stepping relay switch means for synchronizing each cycle of the stepping relay with the frequency of the input signal, and means for controlling the operating frequency of the multivibrator such that its output pulses automatically evenly subdivides the interval between successive pulses of the input signal into a predetermined number of sub-intervals.

A preferred embodiment of the present invention is illustrated in Figure l of the drawing. As shown therein, periodic signals of a pulse train from any suitable source 3 are fed into the grid circuit of tube V-1A through condenser C-l and resistor R-1. The plate circuit of tube V-lA, which together with tube V-1B forms a conventional single-shot multivibrator circuit, extends from the positive 250 volt supply line 4 through resistor R-Z, the tube and resistor R-S to ground. The plate circuit of tube V-lB extends from the positive 250 volt supply line 4 through resistor R-4, the tube and resistor R-3 to ground. The control grid of tube V-1B is cou* pled to the plate of tube V-1A through condenser C-Z and to the positive supply line 4 through resistor R-S.

Th plate of tube V-1B is coupled by means of condenser C-3 to the grid biasing resistor network of tube V-Z which includes resistors R6, R-7, R-8, and R-9. The plate circuit of tube V-2 extends from the positive supply line 4 through the parallel arrangement of the release or trip relay coil K-1A of the step switch S-1, resistor R-lt), condenser C-4, and the energizing coil K-Z of switch S2 and through resistor R-11 and the tube to ground.

The step-type switch S-1 is preferably of conventional design and may take'the form of a so called minor switch which is well known in the art. It therefore preferably has a step drive energizing coil K-1B, a release or trip energizing coil K-lA and three ganged wiper-arm or armature elements S-1A, S-1B, and S1C each of which traverses a separate bank of contacts S-lD, S-IE, and S-1F during each period of the input signal.

Tubes V-3A and V-3B and their associated circuits provide a free running highly asymmetrical multivibrator circuit which as will be more apparent hereinafter generates a plurality of evenly spaced pulses that subdivide the period of the output signal of source 3 into a predetermined number of equal subperiods. The plate circuit of tube V-3A extends from the positive 250 volt supply line 4 through resistor R-12 and the tube to ground and the plate circuit of tube V-3B extends from the positive supply line 4 through resistor R-13 and the tube to ground. The control grid of tube V-3A is coupled to the plate of tube V-3B through condenser C-S and the control grid of tube V-3B is coupled to the plate of tube V-3A through condenser C-6. The control grid of tube V-3B is also coupled to the positive 250 volt supply line 4 through resistor R414 and the control grid of tube V-SA is coupled to ground through resistor R-iS, the series connected triodes V-SA and V-SB, condenser C-7 and variable resistor R-16. The control grid of tube V-SA is preferably connected as shown to the control grid of tube V-3A.

The plate of tube V-3B is coupled to the control grid of tube V-4 through condenser C-S and the grid bias resistor network for tube V-4 which includes resistors R-l', R-IS, R-19 and R-Ztl., The plate circuit for tube V-4 extends from the positive 250 volt supply line 4 through the parallel arrangement of the step drive energizing coil K-lB of switch S-l., the resistor R-Zi and the condenser C9 and through tube V-4 to ground. The suppressor grid of tube V-4 is preferably tied to its cathode and the screen grid is preferably connected directly to the power supply line 4.

Condenser C-lt), which as will be more apparent hereinafter maintains a proper potential across condenser C7, is charged through a circuit that extends from the negative 250 volt supply line 5 through variable resistor R46, condenser C-ltl, the series connected triodes V-6A and V-6B and the variable resistor R-ZZ back to the negative supply line 5. The variable arm of resistor R-ZZ and the control grids of tubes V-6A and V-6B are connected to the wiper arm S-lC of switch S- through variable resistor R-23, switch contact 10 of bank C of switch S-1 is connected to the cathode of tube V-@B and the plate of tube V-6A is connected to switch contact 1 of bank B of switch S-1 through the deenergized contact of switch S-Z and resistor R-24. Manual switch S-S is preferably provided to connect the plate of tube V-4 to the armature S-1A.

In operation tubes V-1A and V-lB of the above described circuit function as a conventional single shot multivibrator. Prior to the occurrence of a pulse from the input signal source 3 tube V-1B normally conducts and tube V-lA is cut-off. Thus, due to the negative bias on its control grid tube V-2 is also cut o and the energizing coils K-IA and K-Z of switches S-l and S-2 are deenergized. A pulse from the signal source 3, however, triggers the single shot multivibrator circuit of tubes V-1A and V-1B, tiring tube V-lA cutting off tube V-lB and delivering a positive pulse from its plate to the control grid of tube V-2. This positive pulse fires tube V-2 and energizes the release or trip coil K-lA of switch S-1 and the pickup coil K-2 of switch S-2. On energization of coil K-lA the armatures S-lA, S-lB, and S-1C of switch S-1 are all returned to their first contact positions in their respective switch banks A,l

B and C and a new pulsing cycle is conditioned to recommence. Energization of coil K-2 of switch S-2 completes the charging circuit for storage condenser CJ whereby the potential which is developed upon the sweep condenser C- in a manner described more fully hereinafter is transferred to condenser C-7.

When conduction through tube V-1B of the multivibrator circuit ceases, tube V-2 again fires, coil K-Z is deenergized, switch S-2 opens, and condenser C-7 is disconnected from the sweep circuit of condenser C-MP. Storage capacitor C-7, however, maintains its charge for the rest of the cycle of operation and as will be more apparent hereinafter provides control of the pulse period of the multivibrator of tubes V-3A and V-3B.

The free-running highly asymmetrical multivibrator of tubes V-3A and V-3B delivers positive pulses of suitable shape and waveform tothe control grid `of the power amplifier tube V-4 which is normally cutoff. Each time tube V-4 fires, the step drive coil of switch S-l is energized and the ganged armatures S-lA, S-1B, nad S-lC thereof are advanced one contact position on their respective contact banks. Each time tube V-4 fires a pulse from the negatively driven plate of tube V-4 is also delivered to the output line 6 and/or through switch S-3 to the commutating bank A of switch S-1.

As the ganged armatures of switch S-l progress bctween their first and tenth contact positions of their respective banks of contacts, condenser C-10 is charged negatively through a circuit that extends from ground through the variable resistor R-16, condenser C-M, tubes V-6A and V-6B and variable resistor R-ZZ to the negative 250 volt line 5. The initial voltage of this charging circuit is set by the variable bottoming control resistor R-16, and the charging rates of condenser C-ltl is set by the variable slope control resistor R-22. When the stepping switch S1 reaches its tenth contact position, the circuit completed through the tenth contact of bank C, shorts out a portion of resistor R-22 in the charging circuit for condenser C-10 and reduces the negative grid bias of tubes V-6A and V-6B, thus reducing the series impedance of the condenser charging circuit. This action increases the charging rate of condenser C-10 and therefore tends to increase the negative potential across condenser C-10 which is transferred to condenser C-7 when the next succeeding input signal pulse from source 3 occurs.

This transferred negative charge on condenser C7 then determines the negative bias of tube V-SA which in turn adjusts the effective resistive discharge path for condenser C-S of the multivibrator circuit of tubes V3A and V-3B and ultimately controls the pulse frequency output of the multivibrator and amplifier tube V-4.

As each input signal from source 3 passes, switch relay coils K-1A and K-2 again become deenergized, and condenser C-10 is discharged through a circuit that includes switch S-Z, resistor R-24, and armature S-1B and the sweep cycle for condenser C-10 is ready to be reinitiated.

It has been found that the above described circuit also automatically adjusts itself to disperse the pulses of the multivibrator of tubes V-3A and V-3B evenly over the interval between successive pulses of the signal input source 3. Thus, if the frequency of the multivibrator of tubes V-SA and V-SB is too great, the stepping rate of switch S-l will be too fast and armature S-lC will remain abnormally long on its tenth contact position whereat as described more fully heretofore the charging rate of condenser C-10 is increased. This will ultimately increase the negative potential across condenser C-10, increase the negative charge transferred to condenser C-7, increase the resistive discharge path of condenser C-S of multivibrator V-S and decrease the frequency of multivibrator V-S during the next succeeding cycle.

If, however, the frequency of the multivibrator V-S is too low, the stepping rate of switch S-l is too slow and armature S-1C will fail to reach its tenth contact position prior to the occurrence of the next succeeding input signal from source 3. Thus, without an increased rate of charge of condenser C-10 during the tenth subinterval the negative voltage across condensers C-l() and C-7 is reduced, the resistive path for condenser C-S is reduced, and the operating frequency of rrr-ultivibrator V-S is increased during the next succeeding cycle. Thus, it is seen that the above described circuit automatically corrects the stepping rate of stepping switch S-l at the end of each input signal cycle.

Although the above described circuit discloses a three bank stepping switch having ten individual contacts, it is to be understood that a switch having any other suitable number of individual contacts could be used to increase or decrease the number of sub-intervals above or below ten between each input signal without departing from the spirit or scope of the present invention.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. Apparatus for dividing intervals between successive pulses of a repetitive input signal into a predetermined number of equal sub-intervals comprising a step relay having a stepping coil and a trip coil; means responsive to each pulse of the input signal for energizing the trip coil of the relay; a sweep circuit; means also responsive to each pulse of the input signal for initiating the sweep cycle of the sweep circuit; a signal generator; means controlled by the sweep circuit for controlling the operating frequency of the signal generator; and means responsive to the output of the signal generator for controlling the step-by-step energization of the stepping coil of the relay.

2. Apparatus for dividing intervals between successive pulses of a repetitive input signal into a predetermined number of equal sub-intervals comprising a step relay having a stepping coil and a trip coil; means responsive to each pulse of the input signal for energizing the trip coil of the relay; a sweep circuit; means also responsive to each pulse of the input signal for imitating the sweep cycle of the sweep circuit; a signal generator; means controlled by the sweep circuit for controlling the operating frequency of the signal generator; means responsive to the output of the signal generator for controlling thc step-by-step energization of the stepping coil vof the relay; and means automatically adjusting the charging rate of the sweep circuit such that the operating frequency of the signal generator evenly subdivides the interval bctween successive pulses of the input signal into a predetermined number of sub-intervals.

3. A circuit for dividing intervals between successive pulses of a repetitive input signal into a predetermined number of equal sub-intervals comprising a step relay having a stepping coil and a trip coil; a single shot multivibrator; a sweep circuit; means responsive to each pulse of the input signal for firing the said multivibrator; means responsive to the output of the said multivibrator for energizing the trip coil of the relay and for initiating the sweep cycle of the sweep circuit; a free-running multivibrator; means controlled by the sweep circuit for controlling the operating frequency of the free-running multivibrator; and means responsive to the output of the freerunning multivibrator for controlling the step-by-step energization of the stepping coil of the relay.

4. A circuit for dividing intervals between successive pulses of a repetitive input signal into a predetermined number of equal sub-intervals comprising a step relay having a stepping coil and a trip coil; a single shot multivibrator; a sweep circuit; means responsive to each pulse of the input signal for firing the said multivibrator; means responsive to the output of the said multivibrator for energizing the trip coil of the relay and for initiating the sweep cycle of the sweep circuit; a free-running multivibrator; means controlled by the sweep circuit for controlling the operating frequency of the free-running multivibrator; means responsive to the output of the freerunning multivibrator for controlling the step-by-step energization of the stepping coil of the relay; and means automatically adjusting the charging rate of the sweep circuit such that the operating frequency of the free-running multivibrator evenly subdivides the interval between successive pulses of the input signal into a predetermined number of sub-intervals.

5. Apparatus for dividing intervals between successive pulses of a repetitive input signal into a predetermined number of equal subintervals comprising a step relay switch having a stepping coil, a trip coil, a plurality of banks of contacts, and an armature for each bank of contacts, each of which successively engages the contacts of its respective bank as the stepping coil is energized and which returns to an original contact engaging position when the trip coil is energized; a condenser; a triode; a circuit which includes the triode for charging the condenser; a free-running multivibrator; means responsive to each pulse of the input signal for energizing the trip coil of the relay switch; means effective after each pulse of the input signal for discharging the condenser; means effective? when the armature of one of the banks of contacts engages its second contact position for completing the condenser charging circuit; means responsive to the potential developed across the condenser for controlling the operating frequency of the free-running multivibrator; and means responsive to the output of the free running multivibrator for controlling the step by step energization of the stepping coil of the relay switch.

6. Apparatus for dividing intervals between successive pulses of a repetitive input signal into a predetermined number of equal sub-intervals comprising a step relay switch having a stepping coil, a trip coil, a plurality of banks of contacts, and an armature for each bank of contacts, each of which successively engages the contacts of its respective bank as the stepping coil is energized and which returns to an original contact engaging position when the trip coil is energized; a condenser; a triode; a circuit which includes the triode for charging the condenser; a free running multivibrator; means including a single shot multivi tor responsive to each pulse of the input signal for energizing the trip coil of the relay switch; means effective after each pulse of the input signal for discharging the condenser; means effective when the armature of one of the banks of contacts engages its second contact position for completing the condenser charging circuit; means responsive to the potential developed across the condenser for controlling the operating frequency of the freerunning multivibrator; and means rcsponsive to the output of the free-running multivibrator for controlling the step-by-step energization of the stepping coil of the relay switch.

7. Apparatus for dividing intervals between successive pulses of a repetitive input signall'into a predetermined number of equal sub-intervals comprising a step relay switch having a stepping coil, a trip coil, a plurality of banks of contacts, and an armature for each bank of contacts, each of which successively engages the contacts of its respective bank as the stepping coil is energized and which returns to an original contact engaging position when the trip coil is energized; a condenser; a triode; a circuit which includes the triode for charging the condenser; a free-running multivibrator; means responsive to each pulse of the input signal for energizing the trip coil of the relay switch; means effective after each pulse of the input signal for discharging the condenser; means effective when the armature of one of the banks of contacts engages its second contact position for completing the condenser charging circuit; means responsive to the potential developed across the condenser for controlling the operating frequency of the free-running multivibrator; and means automatically adjusting the charging rate of the condenser such that the operating frequency of the free-running multivibrator evenly subdivides the interval between successive pulses of the input signal into a predetermined number of sub-intervals; means responsive to the output of the free-running multivibrator for controlling the step-by-step energization of the stepping coil of the relay switch.

8. Apparatus for dividing intervals between successive pulses of a repetitive input signal into a predetermined number of equal sub-intervals comprising a step relay switch having a stepping coil, a trip coil, a plurality of banks of contacts, and an armature for each bank of contacts, each of which successively engages the contacts of its respective bank as the stepping coil is energized and which returns to an original contact engaging position when the trip coil is energized; a condenser; a triode; a circuit which includes the triode for charging the condenser; a free-running multivibrator; means responsive to each pulse ofthe input signal for energizing the trip coil of the relay switch; means effective after each pulse of the input signal for discharging the condenser; means effective when the armature of one of the banks of contacts engages its second contact position for completing the condenser charging circuit; means responsive to the potential developed across the condenser for controlling the operating frequency of the free-running multivibrator; and means for decreasing the internal resistance of the triode such that the operating frequency of the free-running multivibrator evenly subidivides the interval between successive pulses of the input signal into a predetermined number of sub-intervals.

References Cited in the le of this patent UNITED STATES PATENTS 2,645,767 Green July 14, 1953 

